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S6 /CENGINE

INDEX

TECHNICAL SPECIFICATIONS 2

SPECIAL TOOLS 3 - 4

PERIODIC MAINTENANCE 5

LUBRICANTS 6

TROUBLESHOOTING 7 - 14

TIGHTENING TORQUE TABLE 15

ENGINE DISASSEMBLY 16 - 24

ENGINE REASSEMBLY 25 - 37

SPECIAL 3-SHOE CLUTCH DISASSEMBLY/REASSEMBLY 38 - 39

SPECIAL 3-SHOE CLUTCH ADJUSTMENT PROCEDURE 40

ENGINE COMPONENT INSPECTION AND SERVICE 41 - 43

GENERAL PARTS LIST + EXPLODED VIEW TABLES xx

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S6 /CENGINE

SPECIFICATIONSCYCLE ......................................................... - 2 stroke

Nr. of CYLINDERS....................................... - 1

DISPLACEMENT.......................................... - 49.908 cc.

BORE AND STROKE mm............. - 39 X 41.8

CYLINDER MATERIAL ................................. - Aluminium with Ni / Si carbide coating

COMPRESSION RATIO................................ - (15.5 ±0.3) : 1

SPARK PLUG .............................................. - CHAMPION C53

TIMING SYSTEM .......................................... - Reed valve with 4 carbon fibre flaps

MAX. R.P.M. .................................................. - 14500 (rpm) MAX

CARBURETOR ............................................ - 12/14/19 mm diameter

INTAKE MANIFOLD ..................................... - Adjustable

FUEL ............................................................ - EURO UNLEADED NC 623/02 - R.O.N. 95

LUBRICATION OIL MIXER TYPE ................. - 2% AGIP 2T CITY

LUBRICATION WITH OIL PUMP .................. - On request

IGNITION ...................................................... - Electronic with microchip

PRIMARY DRIVE GEAR ............................... - Straight-tooth gears Z 14/59

..................................................................... with safety coupling

..................................................................... Ratio 1:4,21

SECONDARY DRIVE GEAR......................... - Sprocket Z 10 or Z11

..................................................................... Chain type 1/2 x 3/16 roller 7.75

CLUTCH ...................................................... - Automatic centrifugal clutch in oil bath

..................................................................... Adjustable

TRANSMISSION GEAR OIL ......................... - SAE 20 W quantity 250 cc

STARTER...................................................... - Kick starter

COOLING ...................................................... - With liquid pump

TECNICAL SPECIFICATIONS

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S6 /CENGINE

143154

143176

143156

143179

143180

143181

CodeFigure Description

SPECIAL TOOLS

BEARING INSTALLERoutput shaft

BEARING INSTALLERcrankshaft

BEARING INSTALLERoutput shaft

OIL SEAL INSTALLERoutput shaft

OIL SEAL INSTALLERcrankshaft (flywheel + clutch)

OIL SEAL MOUNTING PROTECTIONcrankshaft (flywheel + clutch)

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S6 /CENGINE

140558

143162

143155

SPECIAL TOOLS

CodeFigure Description

OIL PUMP SHAFT INSTALLER(pre-assembled)

FLYWHEEL REMOVER

CRANKCASE PULLER

143294

SPECIAL CLUTCH ADJUSTMENT TOOL

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S6 /CENGINE

PERIODIC MAINTENANCE

RUNNING-IN RECOMMENDATIONS:

During the running-in period, i.e. for approx. the first 500 km on the road, please note as follows:- Do never run the engine at maximum revolutions.- Do never keep the vehicle at maximum speed.- Do not keep the engine at idle speed for longer time.

FIRST MAINTENANCE SERVICE:

to be carried out after 500 - 600 km.

- Replace the engine oil- Check the carburation and adjust if necessary- Check the tightness of nuts and bolts.(See table “tightening torques” pag. 15)

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S6 /CENGINE

LUBRICANTS

N.B.Use original MORINI FRANCO MOTORI spare parts only

N.B. TRANSMISSION OIL LEVEL CHECKRemove the oil filler cap on the clutch cover and check the transmission oil levelthrough window.

RECOMMENDED LUBRICANTS / ADHESIVES

DESCRIPTION CHARACTERISTICS

Transmission oil AGIP RADULA 68 SAE 20W

Assembly of various parts GR/SM2 GREASE

Special assembly GRAPHITISED MOLYCOTE type GREASE

Thread-locking glue LOXEAL 82-21

Clamping glue LOXEAL 83-54

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S6 /CENGINE

TROUBLESHOOTING

Possible CAUSE of the fault

The following flow charts give a general outline of the causes and effects when the engine is notrunning correctly.Descriptions of solutions for a specific cause are general; for more details the reader shouldconsult the disassembly-reassembly manual.

LEGEND OF SYMBOLS

EFFECT (fault noticed by the user)

Possible general SOLUTION to the fault

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S6 /CENGINE

YES

NO

NO

Starting problems

Faulty spark plugor wrong spark plug

heat rating

YES Check spark plug andreplace if necessary.

Engine floodedYES

Start the engine with thethrottle fully open.

Remove the spark plug,rev the engine, install adry spark plug and restartthe engine.

The enginestarts

Sparking starts athigh r.p.m.

Replace the ignition coil

NO

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S6 /CENGINE

YES

YES

YES

NO

NO

YES

NO

Maximum indicated runningspeed cannot be reached

Soiled orclogged

filter

Disassemble, wash sponge with a50% solution of petrol and 2T oil;leave to dry. Clean the filter boxusing compressed air; re-assemble.

Silencerobstructed

Check the silencer for clogging.Replace if necessary.

Cylinderexhaust portsoiled with

carbondeposits

Disassemble the cylinder and checkthat the exhaust pipe is clean. If theexhaust pipe is partly obstructed bycarbon deposits, clean it thoroughlyusing a scraper.

Poorcompression

Disassemble the cylinder head,cylinder and piston.Remove the piston rings, placethem in the cylinder liner and checkthe amount of wear.Replace if excessively worn.

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S6 /CENGINE

YES

YES

NO

Poor acceleration / pickup

Clutch

Irregularacceleration

Check the cluth shoe thickness andthe clutch springs for stretching.If excessively worn they should bereplaced.

Check the exact number of turnsof the air adjusting screw on thecarburetor.

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S6 /CENGINE

YES

YES

YES

YES

NO

NO

YES

YES

Incorrect idling speed

Idling speedtoo high or

too low

Adjust the RPM of the idling speed(with engine warm) by adjusting thescrew on the throttle valve of thecarburetor.

Disassemble the carburetor andclean all parts (nozzles, throttle val-ve, jet needle, float chamber andbody) with solvent and dry by usingcompressed air.

False airintake fromcarburetormanifold

Check the integrity of thecarburetor manifold gaskets.

Check the integrity of the rubbercoupling sleeve that connects thecarburetor and air filter box .

Check the reed valve gasket.

False airintake

from enginecrankshaftoil seals

Check the integrity of thecrankshaft oil seals. Replaceeven if only slightly damaged.

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S6 /CENGINE

YES

YES

NO

NO

YES

Noisy engine

Incorrecttransmission

gearsassembly

Loosetransmission

nut

Transmissionnoise and rearwheel drag atidling speed.

Check the assembly of all gears andparts of the transmission.

Check the tightening torque of theclutch nut.

Check the clutch unit

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S6 /CENGINE

YES

YES

YES

YES

NO

NO

Noisy engine

Noisy gears

Check the oil level.Refill if necessary.

Check the teeth of the drive gearsvisually.Replace if signs of damage orwear are evident.

Noisycylinder

unit

Check the clearance between thepiston and the cylinder. If it doesnot correspond to the prescribedvalue, replace the cylinder andpiston.

Noisycrankshaftbearings

BEARING INSPECTIONRotate the bearing inner race by fin-ger to inspect for abnormal play, noiseand smooth rotation while thebearings are mounted in thecrankcase.Replace the bearing if anythingunusual is found.

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S6 /CENGINE

YES

YES

YES

NO

NO

YES

NO

Smokey exhaust

Percentage ofmixer oil

Replace the fuel in the tank withnew fuel mixed with 2% of the typeof oil indicated in the handbook.

Mixer oilCheck that the oil is 100%synthetic for separate oil mixerpump use.

Carbondeposits

Disassemble the cylinder andremove any carbon deposits;check the silencer for clogging.

Oil mixerpump

Disassemble the oil mixer pumpand check the flow rate.

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S6 /CENGINE

TIGHTENING TORQUES

DENOMINATION TORQUE(Nm)

Cranckcase bolts 10 - 12

Clutch cover bolts 10 - 12

Flywheel cover bolts 3 - 4

Carburetor manifold bolts 9 -10

Stator clamping bolts 3 - 4

Oil pump clamping bolts 5 - 6

Carburetor clamping screw 3 - 4

Kick starter lever bolt 8 - 10

Oil drain plug 8 - 10

Clutch nut 50 - 55+ Loxeal 83-54

Flywheel nut 8 -10+ Loxeal 83-54

Head nuts 12 - 14

Head clamping bolts 10 - 12

Pulley clamping bolts 3 - 4+ Loxeal 83-54

Water pump rotor5 - 6

+ Loxeal 83-54

Spark plug 20 - 25